Porcupinefish, sometimes called spiny puffer or blowfish, is any of several fish with sharp, protective spines covering the body. These spines resemble porcupine quills. When an enemy or intruder scares a porcupinefish, the fish may enter a hole or crack in a rock and fill its stomach with water. The water causes the fish to inflate like a balloon, making its spines stick out. In most porcupinefish, the spines lie flat against the body when the fish are calm.
Most porcupinefish have mainly bluish, brownish, grayish, or greenish coloring, with yellow or white bellies. Some kinds have round black or brown spots. Porcupinefish grow to an average length of 10 to 20 inches (25 to 51 centimeters). All types have two large teeth, one upper and one lower, that stick out like a beak. They use their teeth to feed on sea urchins, small crabs, and other hard-shelled prey. Porcupinefish live in tropical seas.
